the use of SUCH
 

In the FREE LUNCH item of the new word supplement list of Oxford 4th:

There's no such thing as a free lunch.

I think this sentence might be wrong, because THING is a countable noun, and an indefinite article should be inserted before THING;

Apart from this, I, when searching words in online dictionaries, often see this:no such word;

I am not a native English speaker, and so not qualified to challenge Oxford 4th.

Could anyone tell me what's wrong with my statement?

Re: the use of SUCH
 

You don't need an article with singular nouns, when you have a quantifier such as no, each, or every. Compare these sentences :

We have a slight chance of succeeding.
We have every chance of succeeding.
They took each chance they were offered.
We don't have a chance of succeeding.
We have no chance of succeeding.

I never miss a free lunch.
I go to every free lunch which I'm invited to.
There is such a thing as a free lunch - but it's rare.
There's no such thing as a free lunch.

Re: the use of SUCH
 

thank you~~